How ‘mom’ plants teach seeds when to grow

"By understanding how the mother plant uses temperature information to influence the vigor of her seeds we can begin to develop strategies for breeding seeds with more resilience to climate change," says Steven Penfield. (Credit: Evonne/Flickr)

Scientists have discovered how “mother” plants use their memory of the seasons to teach their seeds the best time to germinate.

A new study, using Arabidopsis thaliana as a model plant, shows the mother plant senses temperature and forms a long-term temperature memory. These memories then help progeny seeds figure out what time of year it is and modify their germination rates to ensure their growth and development is coordinated with the seasons.

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If the mother experiences warmer temperatures, it produces more of a protein called Flowering Locus T (FT) which represses production of tannins in the fruit, making seed coats thinner and more permeable. This means they germinate more quickly.

Conversely, if the mother plant experiences cooler temperatures before flowering, it produces less FT protein and more tannins. Seed coats will be thicker and less permeable and will germinate later. In this way, the mother plant can manipulate seed germination to be optimal for the time of year.

With climate change making suboptimal conditions more frequent, a better understanding how plants communicate with their seeds will help scientists optimize seed quality for crops and domestic use.

Seed vigor

For the study, published in the Proceedings of the National Academy of Sciences, researchers measured the hormones in seeds which usually control germination. But, in this case, they found that other signals coming from the mother plant were more important.

“This work demonstrates the importance of growing conditions throughout the life cycle of the plant,” says Professor Ian Graham of the Centre for Novel Agricultural Products (CNAP) at the University of York. “In terms of crop plants, it highlights how adverse environmental conditions can have a negative impact on seed quality.”

“By understanding how the mother plant uses temperature information to influence the vigor of her seeds we can begin to develop strategies for breeding seeds with more resilience to climate change,” adds Steven Penfield of the of the John Innes Centre.

The FT protein is known to influence when a plant flowers depending on the length of day. The research also shows that the influence of this protein on seed dormancy was entirely separate from its influence on flowering time.

The research, funded by the Biotechnology and Biological Sciences Research Council (BBSRC) and the Royal Society, has implications for improving crop yields by helping scientists and growers to adapt how crops respond to changes in climate and temperature.